This invention relates to the production of clean and efficient energy from carbonaceous fuels such as coal, lignite, peat, petroleum coke, biomass, etc., especially as it relates to the generation of electric power and also as it relates to the recycling of the off-gas that is produced during the combustion of these fuels. Such off-gas, when scrubbed and stripped of mercury, is generally made up of nitrogen (N2) and carbon dioxide (CO2). The CO2 is commonly referred to as a “greenhouse gas” and is suspected to contribute to global warming.
Attempts are being made to capture the CO2 where it is generated and to sequester it by introducing it under pressure into such places as deep wells and underground reservoirs for permanent storage—a costly, inefficient, and questionable solution. Other approaches need to be discovered for the useful application of the flue gas instead of sequestering it, which would be beneficial to mankind; the instant invention relates to such useful application.
The applicant has discovered a method herein disclosed that reduces the formation of flue gas by being efficient when generating electric power while still using said carbonaceous fuels, and especially coal, and at the same time converting the flue gas that is generated into a useful by-product—namely, urea. Urea has many uses, especially when utilized as a fertilizer that enhances the growth of biomass as a potentially abundant, renewable energy resource in the agriculture sector.
Before describing the instant invention, it is to be noted that, from the various carbonaceous fuels referred to above, coal will be used as an example as the energy resource for the purpose of describing the invention herein, since more than four billion tons of coal are consumed yearly worldwide, and the majority of this tonnage is used to generate electricity.